Anticonvulsant drugs ineffective for back pain

Anticonvulsant drugs are ineffective in the treatment of lower back and lumbar radicular pain despite prescriptions rising by 500 per cent in the past decade, new research led by the University of Sydney reveals.

Published in the Canadian Medical Association Journal, the systematic review of nine studies report moderate to high-quality evidence that anticonvulsants are not only ineffective but pose a rising risk of adverse events.

Lower back pain affects tens of millions of people globally and is a leading cause of disability. In most cases, lower back pain is non-specific without a clear cause for the pain.

Approximately five to ten per cent of people suffering from low back pain also complain of radiating leg pain down the back of the thigh and sometimes into the calf and foot. This condition known as sciatica, can be accompanied by weakness or sensory changes in the leg.

Anticonvulsant medicines such as gabapentin and pregabalin, also called gabapentinoids, have been shown to be effective in neuropathic pain conditions such as diabetic peripheral neuropathy.

However, previous reviews have found conflicting or insufficient evidence for the use of anticonvulsants for low back pain and sciatica.

Despite this, over 1.3 million prescriptions were written for the anticonvulsant medication pregabalin in Australia between 2013 and 2014.

“Clinically, GP prescription of medicines used to treat nerve pain, such as anticonvulsants, has increased by an astounding 535 per cent in the last ten years,” said study author, Associate Professor Christine Lin of the University of Sydney.

“We have shown, with mostly high-and moderate-quality evidence, that common anticonvulsants are ineffective for chronic low back pain and lumbar radicular pain and are accompanied by increased risk of adverse events such as drowsiness or dizziness.

“There are also reports of suicidal ideation and misuse of these drugs.”

The new findings affirm recent guidelines in the US, UK and Australia that do not recommend the use of anticonvulsants for low back pain.

(Source: The University of Sydney, Canadian Medical Association Journal)